Many companies and other organizations operate computer networks that interconnect numerous computing systems to support their operations, such as with the computing systems being co-located (e.g., as part of a local network) or instead located in multiple distinct geographical locations (e.g., connected via one or more private or public intermediate networks). For example, data centers housing significant numbers of interconnected computing systems have become commonplace, such as private data centers that are operated by and on behalf of a single organization, and public data centers that are operated by entities as businesses to provide computing resources to customers. Some public data center operators provide network access, power, and secure installation facilities for hardware owned by various customers, while other public data center operators provide “full service” facilities that also include hardware resources made available for use by their customers.
The advent of virtualization technologies for commodity hardware has provided benefits with respect to managing large-scale computing resources for many customers with diverse needs, allowing various computing resources to be efficiently and securely shared by multiple customers. For example, virtualization technologies may allow a single physical computing machine to be shared among multiple users by providing each user with one or more virtual machines hosted by the single physical computing machine. Each virtual machine can be thought of as a software simulation acting as a distinct logical computing system that provides users with the illusion that they are the sole operators and administrators of a given hardware computing resource, while also providing application isolation and security among the various virtual machines. Furthermore, some virtualization technologies are capable of providing virtual resources that span two or more physical resources, such as a single virtual machine with multiple virtual processors that spans multiple distinct physical computing systems.
In some data centers that have been set up to provide virtualized computing and/or storage facilities to external customers, a set of resources at the data center may be dynamically divided into resource pools, with each pool being made available for exclusive use by a given customer for designated periods of time. In one scenario, a virtual isolated network comprising numerous compute instances and/or other devices may be set up for a customer at a provider network, and the customer may be granted substantial networking configuration flexibility for the isolated virtual network. For example, customers may assign IP addresses of their choice with the isolated virtual network, set up subnets and routes, and so on, in a manner very similar to the way that network configuration settings could be selected at a customer-owned facility. The costs of connectivity between the customer's own data centers and the customer's resources within the provider network may, however, be dependent in some cases on the types of gateways that can be set up between the provider network and customer networks. Using complex proprietary network devices for gateways may negatively impact cost, performance, and/or resilience to failures in some scenarios. In addition, the use of some types of conventional session-oriented peer-to-peer routing protocols with complicated route selection logic may potentially lead to inefficient or sub-optimal routing for traffic flowing between provider networks and customer networks. Traditional techniques of detecting and responding to failures at various components involved in providing such connectivity can sometimes lead to unnecessarily high false positive rates and/or high false negative rates.
While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.